In the field of gas turbine technology a great deal of effort has been, and continues to be, directed toward improving thermodynamic efficiency by operating gas turbine engines at ever increasing temperatures. These temperatures may exceed the temperatures that some materials within the turbine engine structure can normally tolerate. As such, cooling air may be provided to various turbine engine components using cooling air extracted from other parts of the engine. For example, in some gas turbine engines cooling air is extracted from a plenum at the discharge of the compressor, and is then directed to certain portions of the turbine.
For some gas turbine engines, the air that is extracted from the engine for turbine cooling may be at temperatures that require the air to be cooled before being directed to the turbine. Depending on the type of gas turbine engine, a portion of the fan air flowing in the bypass duct or a portion of the engine bleed air may be continuously redirected and used to cool the extracted turbine cooling air. These configurations can, however, exhibit certain drawbacks. For example, these configurations can result in parasitic losses to overall engine performance and/or increase the risk of a highly unlikely, yet postulated heat exchanger leak.
Hence, there is a need for system and method for cooling air that is extracted from the engine and that is used for turbine cooling that exhibits less parasitic losses to overall engine performance and/or decreases (or eliminates) the risk of a highly unlikely, yet postulated heat exchanger leak, while simultaneously increasing engine specific fuel consumption (SFC) by recuperating heat into the cycle via the fuel, which may or may not be deoxygenated. The present invention addresses at least these needs.